+ my %existingfiles;
+ run_hooks(needsbuild => sub {
+ my $ret=shift->($changed, [@$del, @$internal_del]);
+ if (ref $ret eq 'ARRAY' && $ret != $changed) {
+ if (! %existingfiles) {
+ foreach my $f (@$files) {
+ $existingfiles{$f}=1;
+ }
+ }
+ @$changed=grep $existingfiles{$_}, @$ret;
+ }
+ });